Integrated control unit for an active roll control system for a vehicle suspension system

Abstract

An Active Roll Control System for a motor vehicle that utilizes small valves to control large flows. Flow is supplied by a hydraulic pump which is powered in some fashion by the motor vehicle. Flow is directed to the actuators by a three-position-four-way valve that is controlled by two pairs of small ABS style solenoid valves. This allows for a minimum of power to be supplied by the vehicle to operate the system. Also, this valve arrangement allows a desirable failure mode whereby hydraulic fluid is locked into the hydraulic actuators, there by locking in the anti-roll bar in case of a system failure.

1. A control unit for a roll control system for a vehicle suspension system, the control unit comprising:
 a valve body that is adapted to be connected to a roll control actuator device; 
 a plurality of valves mounted upon said valve body, said valves operable to control said roll control actuator device with at least one of said valves being a solenoid valve; 
 a housing removeably attached to said valve body; 
 a circuit substrate mounted within said housing, said circuit substrate carrying said electronic components, said electronic components operable to selectively actuate said valves; 
 at least one solenoid coil associated with said solenoid valve is carried by said circuit substrate, said solenoid coil being selectively energized by said electronic components to actuate said corresponding solenoid valve; 
 a hydraulically actuated three-position four-way valve mounted upon said valve body, said three-position four-way valve adapted to be connected said roll control actuator device and operable to selectively actuate said roll control actuator device to counter vehicle roll; and 
 two pairs of digital solenoid valves mounted upon said valve body, each of said valve pairs including a normally open valve and a normally closed valve, each of said valve pairs associated with one position of said three-position four-way valve and selectively operable to supply pressurized hydraulic fluid to said three-position four-way valve to change the position thereof. 
 
   
   
     2. The control unit according to  claim 1  further including a two stage pressure relief valve mounted upon said valve body, said pressure relief valve operable to control the pressure of hydraulic fluid supplied to said three-position four-way valve for operation of said roll control actuator device. 
   
   
     3. A control unit for a roll control system for a vehicle suspension system, the control unit comprising:
 a valve body that is adapted to be connected to a roll control actuator device; 
 a plurality of valves mounted upon said valve body, said valves operable to control said roll control actuator device with at least one of said valves being a solenoid valve; 
 a housing removeably attached to said valve body; 
 a circuit substrate mounted within said housing, said circuit substrate carrying said electronic components, said electronic components operable to selectively actuate said valves; 
 at least one solenoid coil associated with said solenoid valve is carried by said circuit substrate, said solenoid coil being selectively energized by said electronic components to actuate said corresponding solenoid valve; 
 a three-position four-way valve mounted upon said valve body, said three-position four-way valve adapted to be connected said roll control actuator device and operable to selectively actuate said roll control actuator device to counter vehicle roll; 
 two pairs of digital solenoid valves mounted upon said valve body, each of said valve pairs including a normally open valve and a normally closed valve, each of said valve pairs associated with one position of said three-position four-way valve and selectively operable to change the position of said three-position four-way valve; and 
 a two stage pressure relief valve mounted upon said valve body, said two stage pressure relief valve including a spool valve as a main stage and a balanced poppet solenoid valve, said spool valve communicating with said balanced poppet solenoid valve, said balanced poppet solenoid valve operable to control the flow of hydraulic fluid through said spool valve whereby the pressure of the hydraulic fluid supplied to said three-position four-way valve is controlled. 
 
   
   
     4. The control unit according to  claim 3  further including a lateral accelerometer, said pressure relief valve being responsive to signals generated by said lateral accelerometer to control the pressure of the hydraulic fluid supplied to said three-position four-way valve for operation of said roll control actuator device as a function of vehicle lateral acceleration. 
   
   
     5. The control unit according to  claim 3  further including a priority valve mounted upon said valve block, said priority valve adapted to be connected to a hydraulic fluid pump and operable to divide a flow of hydraulic fluid between a primary hydraulic circuit and said the pressure of hydraulic fluid supplied to said three-position four-way valve for operation of said roll control actuator device. 
   
   
     6. The control unit according to  claim 5  wherein said hydraulic fluid pump is a power steering pump and further wherein said primary hydraulic circuit is a power steering system. 
   
   
     7. The control unit according to  claim 4  further including an electrical connector mounted upon said housing, said connector adapted to provide an electrical connection between said electronic components and at least one sensor for the roll control system. 
   
   
     8. The control unit according to  claim 4  wherein said electronic components include a microprocessor, said microprocessor electrically connected a plurality of vehicle sensors and responsive to signals generated by said sensors to selectively operate said valves mounted in said valve body to correct vehicle roll about a fore to aft axis. 
   
   
     9. The control unit according to  claim 8  wherein said sensors include said lateral accelerometer and at least one wheel speed sensor and a steering angle detector. 
   
   
     10. The control unit according to  claim 9  wherein said plurality of sensors includes at least one angular rate sensor. 
   
   
     11. A method for controlling the roll of a vehicle comprising the steps of:
 (a) providing a roll control system that includes a valve body that is adapted to be connected to a roll control actuator device, the valve body having a hydraulically operated three-position four-way valve mounted upon thereon that is adapted to be connected a roll control actuator device and operable to selectively actuate the roll control actuator device to counter vehicle roll, the value body also including two pairs of digital solenoid valves mounted thereon with each of the valve pairs including a normally open valve and a normally closed valve, each of the valve pairs associated with one position of the three-position four-way valve and selectively operable to supply pressurized hydraulic fluid to the three-position four-way valve to chance the position of the three-position four-way valve, the roll control system further including a housing removeably attached to the valve body, the housing having electronic components disposed therein, the electronic components being electrically connected to at least one sensor for detecting roll of the vehicle about a fore to aft axis and also being operable to selectively actuate the digital solenoid valves; 
 (b) selectively actuating the valves upon detecting vehicle roll to counteract the vehicle roll; and 
 (c) deactuating the valves upon detecting that the vehicle roll has ended.